Association of leisure time physical activity and abdominal obesity with fasting serum insulin and 2-h postchallenge plasma glucose levels.

AIMS: We investigated the joint associations of leisure time physical activity and abdominal obesity with fasting insulin and 2-h glucose levels and with the risk of impaired glucose tolerance (IGT) and Type 2 diabetes (Type 2 DM). METHODS: A cross-sectional population-based random sample of 1812 Finnish adults 45-74 years of age without a history of cardiovascular disease or diabetes. Relative energy expenditure during the previous 12 months (METh/week), assessed by a questionnaire, was used as a measure of leisure time physical activity. Waist-hip ratio (WHR) was used as a measure of abdominal obesity. IGT and Type 2 DM were assessed by a 2-h oral glucose tolerance test and were defined according to the World Health Organization guidelines. RESULTS: While 2-h glucose and fasting insulin levels increased with increasing WHR (P < 0.001 and P < 0.001, respectively), both of them decreased with increasing physical activity (P = 0.015 and P < 0.001, respectively). The highest 2-h glucose and fasting insulin levels were found among individuals who had most abdominal obesity and were least physically active. Physically inactive individuals had a higher prevalence of IGT and Type 2 DM in all WHR tertiles than physically active persons. CONCLUSIONS: Higher levels of leisure time physical activity are associated with lower 2-h glucose and fasting insulin levels and a reduced risk of having IGT and Type 2 DM, independent of the level of abdominal obesity.     

Diagnostic and therapeutic implications of relationships between fasting, 2-hour postchallenge plasma glucose and hemoglobin a1c values

BACKGROUND: Increased fasting plasma glucose (FPG) and 2-hour postchallenge plasma glucose (PCPG) levels with normal hemoglobin A1c (HbA1c) levels are recognized as risk factors for cardiovascular disease. We undertook this study to determine the relationships between FPG and 2-hour PCPG levels over the normal HbA1c range and to assess the need to control FPG and 2-hour PCPG levels to achieve HbA1c targets recommended by the American Diabetes Association (ADA), International Diabetes Federation (IDF), and American College of Endocrinology (ACE). METHODS: The data of all healthy individuals with HbA1c values less than 7.0% (N = 457) who underwent oral glucose tolerance tests between 1986 and 2002 for either screening as potential research volunteers (93%) or diagnostic purposes (7%) were analyzed. RESULTS: Of 404 individuals with normal HbA1c levels (<6.0%), 60% had normal glucose tolerance, 33% had impaired glucose tolerance, 1% had isolated impaired FPG, and 6% had type 2 diabetes mellitus. Of 161 individuals without normal glucose tolerance, 80% had normal FPG levels. Both FPG and 2-hour PCPG levels increased as HbA1c increased and were significantly correlated (r = 0.63, P<.001), but the 2-hour PCPG level increased at a rate 4 times greater than FPG and accounted for a greater proportion of HbA1c. People who met the IDF and ACE HbA1c targets (<6.5%) had significantly lower 2-hour PCPG levels than those who met the ADA target (<7.0%) (P =.03), whereas FPG levels were similar. CONCLUSIONS: Most individuals with HbA1c values between 6.0% and 7.0% have normal FPG levels but abnormal 2-hour PCPG levels, suggesting that an upper limit of normal for FPG at 110 mg/dL (6.11 mmol/L) is too high and that attempts to lower HbA1c in these individuals will require treatment preferentially directed at lowering postprandial glucose levels.     

A concerted decline in insulin secretion and action occurs across the spectrum of fasting and postchallenge glucose concentrations

Aims/hypothesis Individuals with impaired fasting glucose (IFG) are at increased risk of developing diabetes over the subsequent decade. However, there is uncertainty as to the mechanisms contributing to the development of diabetes. We sought to quantitate insulin secretion and action across the prediabetic range of fasting glucose. Methods We studied a cohort of 173 individuals with a fasting glucose concentration <7·0 mm after an overnight fast using a 75‐g oral glucose tolerance test (OGTT). Insulin action (S_i) was estimated using the oral glucose minimal model, and β‐cell responsivity indices (φ) were estimated using the oral C‐peptide minimal model. The disposition index (DI) for each individual was calculated. The relationship of DI, φ and S_i with fasting and postchallenge glucose, as well as other covariates, was explored using a generalized linear regression model. Results In this cross‐sectional study, S_i and DI were inversely related to fasting glucose concentrations. On the other hand, φ was unrelated to fasting glucose concentrations. S_i, φ and DI were all inversely related to area above basal glucose concentrations after glucose challenge. Multiple parameters including body composition and gender contributed to the variability of S_i and DI at a given fasting or postchallenge glucose concentration. Conclusions/interpretation Defects in insulin secretion and action interact with body composition and gender to influence postchallenge glucose concentrations. There is considerable heterogeneity of insulin secretion and action for a given fasting glucose likely because of patient subsets with isolated IFG and normal glucose tolerance.     

空腹血糖水平与胰岛素抵抗的关系

目的探讨美国糖尿病协会2003年修订的空腹血糖受损(IFG)下限新切点(5·6mmol/L)划分出的中国血糖调节异常(IGR)者是否存在胰岛素抵抗。方法选取糖调节正常者(NGR)9例;以新标准划分的单纯IFG者9例;空腹及糖负荷后血糖均异常的糖调节受损者共20例,其中以新空腹血糖(FPG)切点划分的新联合糖耐量低减(IGT)者10例;以旧FPG切点划分的旧联合IGT者10例;2型糖尿病患者10例。以高胰岛素正葡萄糖钳夹技术测定受试对象的胰岛素敏感性,以静脉葡萄糖耐量试验评估其胰岛β细胞分泌功能。结果(1)新单纯IFG组、新联合IGT组和旧联合IGT组的葡萄糖输注率(GIR)[分别为(7·2±0·8、7·0±1·5、4·8±0·4)mg·kg-1·min-1]明显低于NGR组[(10·3±0·9)mg·kg-1·min-1,P值均<0·05];旧IGT组和DM组[(5·6±1·0)mg·kg-1·min-1]处于相近水平。(2)空腹胰岛素水平在所有IGR组均升高,在DM组下降。(3)新IFG组的胰岛素一、二相分泌量和NGR组相似,但随糖代谢紊乱程度加重,胰岛素一相分泌量进行性下降,而二相分泌水平先逐渐升高,后有所降低。结论(1)新空腹血糖切点划分出的中国IGR者已经出现胰岛素抵抗。(2)随糖代谢紊乱程度的加重,胰岛素分泌缺陷趋于明显。     

Effect of corosolic acid on postchallenge plasma glucose levels

Corosolic acid (CRA) is a substance extracted from Lagerstroemia speciosa L. and has been reported to have biological activities in in vitro and experimental animal studies. In this study, 31 subjects were orally administered 10mg CRA or a placebo, on different occasions, in a capsule 5min before the 75-g oral glucose tolerance test (OGTT) in a double-blind and cross-over design. Nineteen subjects had diabetes, seven had impaired glucose tolerance, one had impaired fasting glucose, and four had normal glucose tolerance according to the 1998 WHO criteria. There were no significant differences in plasma glucose levels before and 30min after the administration. CRA treatment subjects showed lower glucose levels from 60min until 120min and reached statistical significance at 90min. In this study, we have shown for the first time that CRA has a lowering effect on postchallenge plasma glucose levels in vivo in humans.     

Gender differences in the relationships of serum uric acid with fasting serum insulin and plasma glucose in patients without diabetes

OBJECTIVE: To explore gender differences in the relationship of serum uric acid levels with fasting serum insulin and fasting plasma glucose concentrations among an adult Chinese nondiabetic population in Kinmen, Taiwan. METHODS: A total of 7,483 nondiabetic subjects (4,265 women, 3,218 men, aged 30 to 89 years) were involved in a community based epidemiologic study. Those with known or newly diagnosed diabetes were excluded. Overnight fasting blood samples were drawn for serum uric acid, glucose, insulin, lipid, and other biochemical measurements. Demographic and clinical variables including body mass index (weight/height2), waist-to-hip ratio, and blood pressure were measured and documented during face-to-face interviews with structured questionnaires. RESULTS: Stratified analyses revealed that (1) serum uric acid levels were positively associated with hyperinsulinemia and HOMA-insulin resistance in both men and women after adjusting for hypertriglyceridemia, hypertension, obesity, and plasma glucose levels; and (2) serum uric acid levels were more strongly associated with hyperinsulinemia and plasma glucose levels in women than in men. CONCLUSION; Hyperuricemia was positively associated with hyperinsulinemia among patients of both sexes without diabetes. Elevated levels of uric acid should alert physicians to the possibility of insulin resistance. The serum uric acid level was associated with insulin resistance and plasma glucose levels more strongly in females than in males in our study population.     

Association of fasting serum insulin and fasting serum glucose levels with cognitive impairment in Chinese nonagenarians/centenarians

In this study, we examined the association of fasting serum insulin (FSI) and fasting serum glucose (FSG) with cognitive impairment in the very elderly using a sample of Chinese nonagenarians/centenarians. This study used data from a survey that was conducted in 2005 on all residents aged 90 years or more in a district with 2,311,709 inhabitants. FSG, FSI, and cognitive function were analyzed. The sample included 661 unrelated Chinese individuals (aged 90–108 years; mean, 93.52 ± 3.37 years; 67.17 % women; FSI, 6.27 ± 2.27 mU/mL; FSG levels, 4.46 ± 1.45 mmol/L). The prevalence of cognitive impairment was 61.81 % and that of hypoinsulinemia was 31.92 %. Individuals with hypoinsulinemia showed lower cognitive function scores (14.81 ± 5.79 vs. 15.78 ± 5.24, t = 2.160, P = 0.031). No differences in cognitive function score between different FSI and FSG groups were significant, and no differences in FSI and FSG between individuals with and without cognitive impairment were statistically significant. Unadjusted multiple logistic regressions showed that hypoinsulinemia, impaired fasting glucose, or diabetes did not change the risk of cognitive impairment significantly. In summary, we found that in elderly subjects, cognitive function appeared associated with FSI, and higher FSI may be associated with enhanced cognitive function.     

Genetic and environmental factors influencing fasting serum adiponectin in Hispanic children

CONTEXT: Because of its antiinflammatory and insulin-sensitizing properties, adiponectin may play a role in the development of cardiovascular disease and type 2 diabetes. OBJECTIVES: The aims of these analyses were: 1) to estimate the heritability of fasting serum adiponectin; 2) to evaluate the effects of age, sex, and body composition on fasting serum adiponectin; 3) to test for associations between fasting serum adiponectin and diet, fitness, energy expenditure, and fat oxidation; and 4) to determine the relationships between fasting serum adiponectin, insulin and lipids, and blood pressure in Hispanic children. DESIGN: Genetic and environmental factors influencing fasting serum adiponectin were investigated in a cohort of children participating in the VIVA LA FAMILIA Study in 2000-2005. SETTING: This study was performed at the Children's Nutrition Research Center. PARTICIPANTS: The study participants were 805 Hispanic nonoverweight and overweight children, ages 4-19 yr. MAIN MEASURE: The main measure of the study was fasting serum adiponectin. RESULTS: The heritability of serum adiponectin was 0.93 +/- 0.10 (P = 2.4 x 10(-40)). Adiponectin differed by age (P = 0.001), sex (P = 0.04), and weight (P = 0.001) status. Adiponectin levels declined with age, in association with changes in sex hormones and growth factors. Adiponectin was not associated with macronutrient intake, fitness, 24-h energy expenditure, or fat oxidation. Controlling for age, sex, and percent fat mass, adiponectin was inversely associated with homeostasis model of insulin resistance, triglycerides (TG)/high-density lipoprotein cholesterol (HDL-C), and systolic blood pressure (P = 0.001). Significant positive genetic correlations were detected between adiponectin and total cholesterol (rho(G) = 0.19), HDL-C (rho(G) = 0.32), low-density lipoprotein cholesterol (rho(G) = 0.24), and IGF-binding protein-1 (rho(G) = 0.39), and negative genetic correlations were detected between adiponectin and leptin (rho(G) = -0.30), TG (rho(G) = -0.21), TG/HDL-C (rho(G) = -0.33), and IGF-binding protein-3 (rho(G) = -0.32), indicating shared genetic components in their expression. CONCLUSION: The high heritability of adiponectin and pleiotropy seen between adiponectin and leptin, growth factors, and lipids may play a role in the pathogenesis of cardiovascular disease and type 2 diabetes in overweight Hispanic children.     

Preserved circadian rhythm of serum insulin concentration at low plasma glucose during fasting in lean and overweight humans

Circadian rhythms in glucose metabolism are well documented. Most studies, however, evaluated such variations under conditions of continuous glucose supply, either via food intake or glucose infusion. Here we assessed in 30 subjects circadian variations in concentrations of plasma glucose, serum insulin, and C-peptide during a 72-hour fasting period to evaluate rhythms independent from glucose supply. Furthermore we assessed differences in these parameters between normal-weight (n = 20) and overweight (n = 10) subjects. Blood was sampled every 4 hours. During fasting, plasma glucose, serum insulin, and C-peptide levels gradually decreased (all P < .001). While there was no circadian variation in plasma glucose levels after the first day of fasting, serum levels of insulin were constantly higher in the morning (8.00 h) than at night (0.00 h) (P < .001), although the extent of this morning-associated rise in insulin levels decreased with the time spent fasting (P = .001). Also, morning C-peptide concentrations were higher compared to the preceding night (P < .001). The C-peptide/insulin ratio (CIR) decreased during prolonged fasting (P = .030), suggesting a decrease in hepatic insulin clearance. Moreover, CIR was significantly lower in the morning than at the night of day 1 and day 2 of fasting (P = .010 and P = .004, respectively). Compared to normal-weight subjects, overweight subjects had higher plasma glucose, as well as serum insulin and C-peptide levels (all P < .03). Data indicate preserved circadian rhythms in insulin concentrations in the presence of substantially decreased glucose levels in normal-weight and overweight subjects. This finding suggests a central nervous system contribution to the regulation of insulin secretion independent of plasma glucose levels.     

Relationships between fasting plasma glucose levels and insulin secretion during intravenous glucose tolerance tests.

Insulin secretion and glucose disappearance rate were measured in 66 subjects with a wide range of fasting plasma glucose levels. The acute insulin response was present in subjects with fasting glucose levels below 115 mg/dl but was absent above this level. The glucose disappearance rate related to the relative acute insulin response in subjects with fasting glucose below 115 mg/dl and to total insulin response when fasting glucose levels were above 115 mg/dl. A calculated glucose disappearance rate of 1.06 per cent per minute was found when the acute isulin response was zero. All subjects with fasting glucose levels greater than 115 mg/dl had glucose disappearance rates greater than 1.06. These studies support 1) epidemiological data indicating 115 mg/dl as an upper limit of normal for fasting plasma glucose levels and 1.0 per cent per minute as a lower limit of normal for the glucose disappearance rate, and 2) evidence for an important role for the acute insulin response in the determination of glucose disappearance rates during intravenous glucose tolerance tests.     

Instability of fasting blood glucose values in noninsulin-dependent diabetic patients with long-term insulin treatment

We studied serum free C-peptide immunoreactivity (CPR) and the coefficient of variation (CV) of fasting blood glucose values (FBG) in 26 insulin-treated patients with non-insulin-dependent diabetes mellitus (NIDDM) in relation to the duration of insulin treatment. Serum free CPR responses during 100 g oral glucose tolerance test (OGTT) were significantly lower in patients with insulin treatment for five years or more than in those with insulin treatment for less than five years although their previous immunoreactive insulin (IRI) responses during OGTT before insulin treatment showed no significant difference. CV of FBG was found to be significantly higher at the time of this study (20.6 +/- 7.8%, mean +/- SD) than at the second year of insulin treatment (15.3 +/- 7.7%, P less than 0.05) in the patients with insulin treatment for five or more years but did not show any significant difference in patients with insulin treatment for less than five years at the corresponding times. Thus we measured CV of the FBG in NIDDM patients at various intervals during the long-term insulin or oral hypoglycemic agent treatment in another study. In 20 patients with insulin treatment, CV of FBG was found to be significantly different among the various intervals during insulin treatment (P less than 0.0025). It was significantly higher at the eight year (22.2 +/- 8.6%) and 12th year (21.9 +/- 9.1%) than at the second year (14.9 +/- 6.1%) and fifth year (15.0 +/- 6.7%) of insulin treatment (P less than 0.025, P less than 0.025; P less than 0.05, P less than 0.01, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

Long-term effects of a carbohydrate-rich diet on fasting blood sugar, lipid profile, and serum insulin values in rural Bengalis

Background: The prevalence of Type 2 diabetes is increasing in rural areas of India, where there is also often a lack of health infrastructure. Thus, a proper dietary study with the view of combating diabetes is essential. The aim of the present study was to determine the long‐term effect of a carbohydrate‐rich diet in rural Bengal. Methods: Volunteers (n = 320) were selected from three villages in Kharagpur and were randomly divided into a control and experimental group (n = 160 in each). The design of the study was such that non‐significant differences in any of the dependent variables were maintainted prior to the application of control or treatment modes. In the control group, volunteers consumed <70% carbohydrate as part of their diet, whereas in the experimental group carbohydrate consumption was >70%. Blood samples from both groups were collected on yearly basis for 5 years and fasting blood sugar (FBS), lipid profile and serum insulin values were analyzed. Results: The blood biochemistry profiles were monitored before the start and at the end of the study. The results indicate that increased intake of carbohydrate causes significant increases in FBS (P < 0.05) and serum insulin (P < 0.05), as well as changes in the lipid profile, particularly triglycerides (P < 0.05) and very low‐density lipoprotein–cholesterol (VLDL‐C; P < 0.05). Conclusions: The effects of increased carbohydrate on FBS, serum insulin, triglycerides and VLDL‐C indicate that a proper nutritional policy needs to be implemented for this population of rural, low‐income Bengalis.     

Joint analysis of fasting and postprandial plasma glucose and insulin concentrations in Venezuelan women

AimsPlasma glucose and insulin concentrations in fasting and postprandial reflect the metabolism of glucose by the human body and are useful in the diagnosis of metabolic diseases, such as diabetes and insulin resistance. In this work, these concentrations are jointly analyzed in Venezuelan women and 28 classes that better specify each metabolic condition are generated.Materials and methodsEach class comprises a combination of fasting and postprandial ranges of glucose and insulin concentrations defined in the literature as normal, impaired and diabetic. A hypothesis test was used to find statistically significant differences between the classes, and confidence intervals for age and glucose and insulin concentrations were defined for each class.Results and conclusionThe process of deterioration of glucose metabolism advances with the age of the subject, more than half of the prediabetics have impaired glucose levels in fasting but normal in postprandial and normal insulin levels in fasting and postprandial, and one third of diabetics have diabetic glucose levels in fasting and postprandial and normal insulin levels in fasting and postprandial. This categorization of subjects would allow the application of a more specific treatment and the possibility of predicting the progress of the metabolic disorder.     

Genome-wide scans for heritability of fasting serum insulin and glucose concentrations in hypertensive families

Aims/hypothesis The heritability of fasting serum insulin and glucose concentrations in non-diabetic members of multiplex hypertensive families is unknown.Methods We calculated the familial aggregation of fasting serum glucose and insulin concentrations and performed a genome-wide scan to assess whether quantitative trait loci contribute to these phenotypes in 2,412 non-diabetic individuals from 1,030 families enrolled in the Hypertension Genetic Epidemiology Network (HyperGEN) in the Family Blood Pressure Program.Results The heritability (±SE) of fasting serum insulin was 0.47±0.085 in European Americans and 0.28±0.08 in African Americans (p<0.0001 for both), after adjusting for age, sex, and BMI. A genome-wide scan for fasting serum insulin yielded a maximum log of the odds (LOD) score of 2.36 on chromosome 5 at 20 cM (p=0.0004) in European Americans, and an LOD score of 2.28 on chromosome 19 at 11 cM (p=0.0004) in African Americans. The heritability of fasting serum glucose was 0.5109±0.08 in the former and 0.29±0.09 in the latter (p<0.0003 for both) after adjusting for age, sex and BMI. A genome-wide scan for fasting serum glucose revealed a maximum LOD score of 2.07 on chromosome 5 at 26 cM (p=0.0009) in European Americans.Conclusions/interpretation These analyses demonstrate the marked heritability of fasting serum insulin and glucose concentrations in families enriched for the presence of members with hypertension. They suggest that genes associated with fasting serum insulin concentration are present on chromosomes 19 and 5, and that genes associated with fasting serum glucose concentration are on chromosome 5, in families enriched for hypertension.An erratum to this article can be found at     

Effect of glucagon antibodies on plasma glucose,insulin and somatostatin in the fasting and fed rat

Summary A potent high-titre glucagon antibody pool was used to induce a state of acute glucagon deficiency in order to investigate the importance of glucagon in maintaining euglycaemia in the fed and fasted anaesthetised rat. Binding characteristics of the antiserum and evidence of its neutralisation of the biological effects of exogenous glucagon are described. The amount of antibody administered was capable of neutralising up to 12 times the total content of glucagon (approximately 1nmol) in the rat pancreas. The hyperglycaemic response to 1.43 nmol exogenous glucagon was significantly inhibited in the rat by glucagon antibodies given intravenously or intraperitoneally (p < 0.001). However, no changes in plasma glucose occurred in rats fasted 16 h (4.35±0.1 mmol/l or 24 h (4.0±0.05 mmol/l) after antibody administration. The same dose of glucagon antibodies produced no change in plasma glucose (6.1±0.2 mmol/l), immunoreactive insulin (1.85±0.05 g/l) or immunoreactive somatostatin (110±30 ng/l) in rats after antibody administration. Antibody excess, equivalent to a binding capacity for glucagon of 40 nmol/l in the plasma of recipient animals, was demonstrable at all times after passive immunisation. The absence of any affect on glucose concentrations following immunoneutralisation of glucagon suggests that glucagon secretion may not be a major factor in the maintenance of euglycaemia in the rat.     

阿尔茨海默病患者空腹血糖和真胰岛素与载脂蛋白E基因型的分析

目的检测并分析阿尔茨海默病(Alzheimer’s disease,AD)患者空腹血糖和真胰岛素及载脂蛋白E(apoE)基因多态性,探讨AD患者体内胰岛素变化。方法随机选取70例正常人(对照组)、55例AD患者(AD组),检测其空腹血糖和真胰岛素及apoE基因多态性,将AD患者按轻、中重度和不同apoE基因型分组后与相应的对照组进行比较。结果AD患者各组空腹血糖与相应对照组比较,差异无显著性意义(P>0.05);轻度AD组真胰岛素较对照组差异无显著性意义(P>0.05),中重度AD组真胰岛素较对照组升高,差异有显著性意义(P<0.05);无apoEε4基因AD组较无apoEε4基因对照组真胰岛素升高,差异有显著性意义(P<0.05),有apoEε4基因AD组、有apoEε3基因AD组及无apoEε3基因AD组分别与相应对照组比较,真胰岛素差异无显著性意义(P>0.05)。结论AD患者体内胰岛素异常,在疾病的严重程度及不同apoE基因型之间有差异。